Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already carry destructiveHint=true, idempotentHint=true, and readOnlyHint=false. The description adds genuine value beyond them: the return signal when the item is absent ('removed: false') and the cross-user outcome ('not_found'), both of which an agent needs to handle results correctly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact clauses, with the ownership scope leading and the two outcome codes following. Nothing is repeated from the title or schema, and no sentence is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple three-parameter mutation, the definition covers scope, the resulting codes, and the permission boundary. It does not state authentication prerequisites explicitly or whether removal is reversible, but nothing critical for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 67%; list_id is documented as coming from list_my_lists and locale is documented inline. The description adds nothing about product_slug, the one undocumented parameter, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Removes a product from one of the signed-in person's lists'), which distinguishes it from add_to_list and from delete_list/remove_favorite. It never names a sibling explicitly, so the differentiation is inferential rather than stated.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the ownership scoping ('signed-in person's lists'), but there is no explicit guidance on when to use this versus add_to_list's inverse, remove_favorite, or delete_list when a whole list should go. An agent must infer the boundary from names alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.